Development of a Shape Memory Alloy Composite Actuator for the Whole Skin Locomotion Robot

In this paper the development of a novel actuator is presented that utilizes a flexible shape memory alloy composite (SMAC) to generate motion for the Whole Skin Locomotion (WSL) robot. The WSL mechanism for mobile robots is inspired by how single celled organisms use cytoplasmic streaming to generate pseudopods for locomotion. This mobility mechanism is directly suited for robots traversing tight spaces where flexibility and shape changes are deemed necessary. The body of the WSL robot is comprised of an elongated fluid filled torus which turns itself inside out in a single continuous motion, effectively generating the overall motion of the cytoplasmic streaming ecto-plasmic tube in amoebae. The eversion of the entire outer skin of the WSL is driven by a pair of the SMAC actuators in the shape of a torus. The actuation of the SMAC is accomplished by the individually controlled shape memory alloy wires embedded in an elastic beam that is then deformed into a torus shape. The design of the first prototype, fabrication efforts as well as a qualitative model of the behavior are presented. Experiments validating aspects of the modeling are also discussed.